Llŷn y garreg ateb : (Darlith a draddodwyd yn Ysgol Botwnnog, Nos Fercher, Mawrth 23ain, 1994) by Arfon Huws. ISBN 187047015X. Published by Cyngor Sir Gwynedd, Adran Diwylliant a Hamdden in 1995. Publication and catalogue information, links to buy online and reader comments.